1. Technical Field
The present invention relates to an electronic device and a touch-sensing method. More particularly, the present invention relates to an electronic device and a method of sensing touch operations on two touch sensors.
2. Background
FIG. 1 is a schematic diagram showing a conventional electronic device 100. The electronic device 100 is a touch-sensitive device, such as a smart phone, a personal digital assistant (PDA), a tablet personal computer (PC), a notebook PC, or a desktop PC. The electronic device 100 includes a touch display 110 and some virtual keys 120. Each virtual key 120 may detect touch operations of the user in the same way as the touch display 110 does.
FIG. 2 is a cross-sectional view showing the electronic device 100. The touch display 110 includes a cover glass 140, a touch sensor 150 and a liquid crystal module (LCM) 160. The size of the display area 132 is the same as the size of the cover glass 140 that exposes the images displayed by the LCM 160. The touch active area 131 is the touch-sensitive surface of the electronic device 100. The size of the touch active area 131 is the same as the size of the touch sensor 150. The touch sensor 150 extends beyond the size of the cover glass 140 that exposes the images displayed by the LCM 160 and the LCM 160 and extends under the virtual keys 120. Therefore, the touch active area 131 covers the display area 132 and the virtual key area 133. The user may make selections by simply touching the display area 132 or the virtual key area 133 via a finger or stylus. In general, the electronic device 100 may recognize the positions of touch events induced by the user on the touch active area 131 by scanning the touch sensor 150 and then perform actions based on the touch events.
In FIG. 2, the touch sensor 150 and the LCM 160 are separate components. Since fabrication technology is always getting improved, there is always a trend of integrating related components into a single one to reduce complexity and cost of the entire system. Recently, the in-cell and on-cell technology enable the integration of the touch sensor and the LCM.
For example, FIG. 3 is a cross-sectional view showing another conventional touch-sensitive electronic device 300. The integrated LCM 360 in the electronic device 300 replaces the touch sensor 150 and the LCM 160 in the electronic device 100. There is a touch sensor (not shown) integrated with the LCM 360. However, since the touch sensor integrated with the LCM 360 has the same size as that of the LCM 360, the touch active area 331 of the electronic device 300 covers the display area 132. The virtual keys 120 of the electronic device 300 cannot work because there is no touch sensor under them.